- Wavelength is a fundamental concept in wave physics, describing the spatial distance between two successive points in phase on a wave—typically measured from crest to crest or trough to trough in transverse waves, or compression to compression in longitudinal waves.
- It is commonly represented by the Greek letter λ (lambda) and plays a key role in understanding the behavior of all types of waves, including light, sound, water, and electromagnetic waves.
- In physics, wavelength is inversely related to frequency, which is the number of wave cycles that pass a point per unit of time. This relationship is described by the equation:
λ = v / f,
where λ is the wavelength, v is the speed of the wave, and f is the frequency. As frequency increases, wavelength decreases, assuming the wave speed remains constant. This inverse relationship is fundamental to wave theory and explains phenomena such as the color spectrum in visible light, where violet light has a shorter wavelength and higher frequency than red light. - In the electromagnetic spectrum, wavelength determines the type and energy of radiation. Radio waves have the longest wavelengths (ranging from millimeters to kilometers), while gamma rays have the shortest (on the order of picometers). Visible light occupies a narrow band in this spectrum, with wavelengths from about 400 nanometers (violet) to 700 nanometers (red). Each wavelength within this range corresponds to a different perceived color.
- In acoustics, the wavelength of a sound wave determines its pitch. Longer wavelengths correspond to lower-pitched sounds, while shorter wavelengths correspond to higher pitches. The speed of sound in air (approximately 343 meters per second at room temperature) and the frequency of the wave determine the sound’s wavelength.
- Wavelength also plays an essential role in wave interference, diffraction, and resonance. For example, in optical systems, devices like diffraction gratings and interferometers exploit wavelength differences to measure tiny distances or to analyze light composition. Similarly, in quantum mechanics, the de Broglie wavelength describes the wave-like nature of particles, revealing that even matter exhibits wave properties at very small scales.
